TCL LCD20W5HE - 6.2 Start-up Failure (Yellow LED)

20” LCD TV TCL LCD20W5HE
20
6.2 Can not start (LED indicator yellow)
NG
Repair the keyboard
OK
Check 5V_SB
NG
Return to “6.1”
Check 3.3V_SB
Replace U703 or F702
OK
NG
Check PWR_ON signal
OK
NG
Check Q703, Q708, Q704, Q911
NG
Replace Q703 or Q708 or Q704 or Q911
Check U402, U403
NG
Replace U402 or U403
Check I
2
C communication
OK
Check Q940 (VCC3)
NG
Replace Q940
Check PFC circuit
NG
Replace IC901 or Q901
OK
OK
Check main board power supply
Check keyboard
NG
Replace panel
Check Panel inverter board